To implant intervertebral prostheses, special insertion instruments are needed because of the difficult access. In order to ensure that the intervertebral prosthesis can be held by the insertion instrument, it is known to provide bores on the ventral end face of the closure plates, which bores point in the direction of insertion and into which correspondingly shaped pins on the insertion instrument engage (U.S. Pat. No. 5,314,477 and WO-A-0119295). Although this type of securing is quite safe, the space needed for the bores means that it is not possible to reduce the size of the end face and thus of the overall closure plate. This design is not really suitable for use in confined conditions.
In another known intervertebral prosthesis system (EP-A-1 306 064), no bores are provided, and instead the insertion instrument has two pairs of gripping members which are connected rigidly to one another and which in each case hold a closure plate between them by friction. For very small implants, of the kind which are used in the area of the cervical spine and which have to be positioned very precisely, this may be too unreliable.
The object of the invention is to make available an improved arrangement of intervertebral endoprosthesis and insertion instrument which is adapted in particular to the requirements of implantation in confined conditions, as apply in particular in the area of the cervical spine.